The present invention relates to watertight fasteners, and more particularly to a watertight fastener for mounting a prefabricated bathtub surround on a wall.
A panel of a prefabricated bathtub surround is typically formed of an outer stone or stone like veneer and an inner substrate, the latter being used in conjunction with a fastener to secure the outer veneer to the wall (or more particularly to a metal stud of the wall) over the bathtub. Such a fastener must serve two paramount functions. First, it must provide support for the surround panels so that the surround panels are held in place on the wall over the bathtub and in proper relationship to one another. Second, it must provide a fluid-tight seal which precludes water from attacking the wall by passing between the surround and the bathtub or between the adjacent panels forming the surround. If water succeeds in reaching the wall, the wall, the metal stud thereof and/or the inner substrate of the surround panels may over time be eroded to the point where it can no longer provide its designated structural support function.
The known fasteners for mounting the surround panels on the wall were not entirely satisfactory in use. Prior art fasteners tend to concentrate on the fastening function, leaving to a separate sealing element the sealing function. This increased the difficulty and cost of construction as at the work site two separate elements had to be properly located and then maintained in place as the surround was mounted. Second, the fasteners provided adequate support for the surround panel against displacement in one direction, but not against displacement in the opposite direction. For example, the fasteners providing vertical support for the surround panel did not prevent or resist upward movement of the surround panel relative to the fastener. Third, if the portion of the fastener entering an opening in the surround panel was of sufficient thickness to fill the opening and thereby prevent movement of the surround panel towards and away from the wall, then it was difficult to fit the surround panel opening over the fastener portion. On the other hand, if the surround panel opening was large enough to easily receive the fastener portion, then the fastener portion was unable to provide stability.
The prior art sealing elements were not entirely satisfactory in use either. They provided no support function other than that irreducible minimum which is provided by any element which is capable of only finite compression; for the purposes of the present application, such an element is not considered as providing any support function. They had to be disposed in place separate from the fasteners and had to be maintained in such positions against dislodgement by the surround being put into its mounted position.
Accordingly, it is an object of the present invention to provide a watertight fastener which combines the functions of a fastener and a sealing element while acting as a one-piece unit.
Another object is to provide such a fastener which obviates the need for a separate sealing element.
A further object is to provide such a fastener which not only precludes movement of a surround panel in one direction, but also resists displacement of the surround panel in the opposite direction relative to the fastener.
It is also an object of the present invention to provide such a fastener which easily receives the surround panel and yet provides resistance to displacement of the surround panel towards or from the wall.
It is another object to provide such a fastener which is easy and economical to manufacture and use.